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China’s Sinuous 'Lucky Knot' Bridge Has No Beginning and No End

The Lucky Knot bridge is a steel truss bridge that spans the Dragon King Harbor River in Changsha, China.

The undulating bridge connects four different public spaces.

It's essentially three bridges knotted into one.

The 1,001 stairs lead pedestrians through a labyrinth.

The intersection points of the three bridges bolster the structure.

They also provide passageways for pedestrians to cut from one bridge to the next.

The Lucky Knot bridge is a topologically fascinating structure. The bright red truss bridge, which spans the Dragon King Harbor River in Changsha, China, twists and knots like a tangled shoestring. Its steely, 600-foot spine swoops into an infinite loop, with no clear end point. “We refer to it as a Mobius ring," says Michel Schreinemachers, a partner at Next Architects, the firm that designed the bridge. “It’s a never ending shape.”

Next is known for its unorthodox crossings. It once designed a bridge made for bats (and pedestrians) in a town Monster. It built another in The Netherlands that's partially submerged in water on certain days of the year. Visually, the Lucky Knot is its wildest yet.

It's effectively three bridges woven into one, which meant Next had to ensure all three forms worked together as a single structure. Schreinemachers knew the bridge needed to be at least 78 feet above the river level to allow boats to pass beneath it. He also knew that the steepest pitch line could be no greater than 34 degrees, to keep the stairs pedestrian-friendly. These parameters kept the bridge's pathways wide and its curves flat. The result looks a bit like a children’s roller coaster.

Next Architects

“Once we developed the basic shape of the bridge, the main challenge lay in designing the intersection that enables pedestrians to go from one route to the other,” Schreinemachers says. The bridge overlaps at five connection points. These provide structural support and serve as pathways by which pedestrians can access different routes. To get from one bridge to the next, people can walk through moon gates, the circular passageways used in traditional Chinese garden architecture.

The Lucky Knot, in other words, is more than a utilitarian pathway."Bridges also have a highly metaphorical quality," Schreinemachers says. "They connect not only in a physical sense, but also people, places, needs, and experiences." If you want, it'll get you one side to the other. But that's far from the only point of a bridge with neither a beginning nor an end.